NEETChemistryClassification of Elements and Periodicity in Properties
Why is the electron gain enthalpy of O or F less negative than that of the succeeding element (S or Cl)?
Options
- AOxygen and fluorine have smaller atomic sizes.
- BOxygen and fluorine have lower effective nuclear charges.
- COxygen and fluorine have higher electron-electron repulsion.
- DOxygen and fluorine have larger atomic radii.
Correct answer
C. Oxygen and fluorine have higher electron-electron repulsion.
Step-by-step solution
The electron gain enthalpy of O or F is less negative than that of the succeeding element (S or Cl) because when an electron is added to O or F, the added electron goes to the smaller n = 2 quantum level and suffers significant repulsion from the other electrons present in this level.